2G Jailbreak manual IP Adress change

[circlemaker]

Hi, I got a second hand iPhone, jailbroke/unlocked it put in a Virgin Sim. I have turned off push, Wi-Fi, Notifications, Location services, Data Roaming. There is nothing entered in Network - VPN, Cellular Data - APN, Username, Password. Yet when I am not using the phone for the internet, my bill shows usage to the internet. Virgin say the phones hardware is assigned to the old users IP Adress and gave me an IP Adress a username, Password and Data Carrier name to add (under APN) to use so that the phone will only go via virgins data provider. Now, here's the problem, I can see where to put the Username, Password and Dataprovider strings, however I cannot see where to put the new IP Address, can anyone please advise as Virgin said they were not allowed to advise on this matter - only to give the details to enter in. I suspect I need to either do a complete info wipe of all data on iPhone (to remove the old IP Address)and/or install something from Cydia, but I am unsure what I need to do to enter the specific IP Address. Can anyone help as each day it is costing me.

and I am running 3.0.1 f/w.